Improvement in pneumatic switch-signals



n r ana.- PN EUMATIC SWITCH SIGNAL.

N' 1s3,4s7, Patent ed 124.1376.

g Q 0 B 'INVENTOR.

N.PE|'ERS. PHOTO-LITHOGRAFHEH. WASHINGTON D C UNITED STATES:

PATENT Qrrroa.

DAVID A. BURR, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN PNEUMATIC SWITCH-SIGNALS.

Specification forming part of LettersPatent' No. 1 83,487, dated October 24, 1876; application filed May 22, 1876.

To all whom it may concern:

Be it known that I, DAVID A. BURR, of Philadelphia, in the State of Pennsylvania, have invented a new and useful Improvement in Indicating Apparatus for Pneumatic Switch- Movements, which isfully set forth and described in the following specification and accompanying drawings.

This invention is designed to secure an accurate indication, in a signal-tower or other station from whence a railway-switch is moved by means of compressed air, of the changes made in the position of the switch so soon as its movement in either direction iscompleted.

It consists, first, in combining with the supply-pipe delivering compressed air to the switch apparatus, and with the main pipes conveying air from said supply to the opposite ends of the piston actuating the switch, two cooks, the one (or main cock) to be moved by hand, at the pleasure of the switch-operator, as required, and the other (the'indicating-cock) to be moved automatically by means of a secondary piston, actuated in opposite directions by a return of air from the cylinder of the switch-piston at the completion of its stroke, the position of the secondary piston, as indicated by a pointer or slide on a'suitable board, serving to denote the positionto which the switch has been moved. The portsin these cocks are so arranged, and the main air-pipes to the switch and secondary pistons are so connected therewith, as that by a movement of the main cock air will be admitted from the supply-pipe through connected ports in both cocks, and through one of the main pipes, to

- one end of the switch-piston, and thence, when the piston has completed its stroke, back through the opposite main pipe and other ports in the two cocks to: one end of the secoperated thereby, an indicating-slide, or a This movement of the secondary.

pointer, as its equivalent, whose movement, indicated upon or through a dial-board, shall correspond with andbe produced by the move; ment of said piston.

It consists, third, in coupling together the main air-pipes leading from the maincock to a pneumatic switch-piston by means of two cross-pipes, each of which will afford direct communication between said main pipes, and in determining and controlling the flow'of air in the cross-pipes by means of valves or cocks, arranged and operating to allow the air to pass through each pipe in one direction only, this flow of air through either pipe being dependent upon the opening of the valve or. cook by the action thereon of the switch in coming to its normal position at the completion of its movement. or cocks and cross-pipes is such as that the opening of the valve or cook in either pipe by In the accompanying drawings, Figure 1 is I a side elevation of the case containing the main and indicating cocks, including an end View of the indicating-piston cylinder and a transverse section of the indicating-board;

Fig. 2, a central vertical section transversely through the cooks and longitudinally through the indicating-piston cylinder, illustratingthe arrangement of ports and pipe-connections; and Fig. 3, a plan view, illustrating, on a reduced scale, the combination and'arrangement of the main and indicating cocks and piston, with the switch-piston and cylinder, the cross connecting-pipes, and the movable rails of a switch, the controlling-valvesv in cross-pipes being shown in section.

A is ametallic block or casing, in which are formed .suitable seats for the main and indicating cock keys 0 and D, and also air-passages forconnectin g the ports of the cocks with each other or with outer pipe-connections. The inner perimeter of each of the key-seats is pierced with six equal ports,,arrangedat equal distances apart. The opposite ports in the one seat are arranged in planes at right'angles to opposite ports in the other seat. In the form of The combination of the valves casing illustrated in the drawing, the opposite ports for the indicating-cock are formed in .a horizontal, and for the main cock in a vertical, plane. The opposite ports E F of the main cock 0, arranged in a vertical plane, extend outwardly through the casing A, the one, E, being connected with a pipe, G, for supplying compressed air to the apparatus, and the other, F, opening freely outward, to form an exhaustvent. The opposite ports H and I of the indicating-cock D extend also outwardly, and

are connected, respectively, with the main of like passages, S S.

The key ot the cock D is provided with two equal abutments, arranged to cut off any two opposite ports and establish communication between the two adjacentports remaining on either side thereof, as shown in Fig. 2. The key of the cock 0 is provided with three equal "abutments, each wide enough to cover and close a port, the intervening recesses being wide enough to establish free communication between any two adjacentrports, as shown in Fig. 2.

B is a cylinder, inclosing a double piston, M,'whose rod extends outwardly through a suitable stuffing-box at one end thereof. This rod terminates in a plate, N, slotted to engage the pin of a small crank, P, (see Fig. 1, and dotted lines, Fig. 2,) secured upon the end of the cock D, so as to turn the latter. The crank T is so adjusted upon the key of the cock D. with reference to the engaging-slot N,

as that when the piston has completed its stroke in one direction, communication shall be established between the ports H and S and I and L, and in the other between the ports B and L and I and S, respectively, the ports L and S in the one case, and S and L in the other, being thereby closed. 0 is a vent formed centrally in the cylinder B, to permit a free exhaust of air from the cylinder at the completion of the stroke of its piston in either direction. Q is a slide, connected with, and secured to, the rod of the piston M, so as to move therewith. This slide is arranged to move behind a board, R, over a dial-aperture, r, pierced therein. The aperture is of such size as that one half or division only of the slide may be seen through it, and the slide is painted in twd different colors, or with difl'er- 'ent letters or symbols, one of the colors orletters, as it appears through the aperture 1", indicating a given position of the piston, and the other its opposite position. W is a pointer, secured to the end of the key of the cock D, which is made to project out through the board It to receive it. This pointer will serve .Ias an equivalent device for the slide Q, to indicate on the face of the board thepositiou of the cock-key, and consequently of the piston M, whichhas actuated it. T T" are pipes,

connecting the opposite ends of the iudicatingpiston, respectively, with the air passages and ports L and L. U U U U are the fixed rails, and V V the movable rails, of a railwayswitch operated by means of a pneumaticpiston, K. X X are cross-pipes, connecting directly with each other the main pipes H and l, which lead from the main and indicating cocks to the opposite ends of the switch-pis' ton K. b b are valves, interposed in the crosspipes X X, to control the flow of air through them, and which are, respectively, so placed therein as that the direction in which the air may flow through one cross-pipe shall be invariably opposed to that in which the air may flow through the other.

Each valve b b is arranged to be closed by a spring of such power as shall keep the valve closed against any degree of airpressure which it is contemplatedto use in the work. ing of the apparatus, but which will readily yield to the. superior pressure of the switch when moved against the valve-stem to;open it. The valve-stems are guided in suitable bearings, and extend outwardly through suit able stufiing-boxes. The valves b b and crosspipes X X are so located on opposite sides of one or both of the movable rails V V of the switch as that when the movement of the rails is completed in either direction, the stem of the valve b in that side shall he struck there by and the valve forced open, its springoperating to close it automatically so soon as the stem is relieved from contact with the rail, and to keep it closed and prevent any flowot' air through the pipe until again forced open by the switch. i

Check-valves a a may, however, be placed in each of said cross-pipes X X, on that side of the governing-valve b or b from which the air must arrive to pass through thevalve, as an auxiliary device, to prevent the latter from opening if its spring becomes weak or, i115 stead thereof, I contemplate substituting for the spring-actuated iuppetvalves b b,lillustrated in the drawipgs, as an equivalent there for, either simple slide valves or ordinary cocks; these slide-valves'or cocks to be each closed automatically, eitherby the power of a suitable spring arranged to be compressed by the opening of the valve, or else by the reverse movement of the switch itself, operating against a stop'or catch upon an extension of the valve-stem, or of the cock-rod.

It is evident, also, that the valves b b, in-

substantially as described", by means of separate pipes and fittings, instead of the airpassages illustrated in the drawing, Fig.2.

In the use of this apparatus, the casing A, with its cock and the indicating-piston cylinder B, and the indicating devices, are placed in a railway-station or tower, and connected by pipes, as described, with the cylinder and piston for operating a switch upon the railroad.

The operation of this apparatus is as follows: If the switch be thrown, for instance, to the north, (in which case its position will be indicated by the letter N through the dialopening 7' of the indicating-board R, or otherwise, by the pointer W turned and pointing 'to the corresponding letter painted upon said board,) and it is required to move it over to its south position, the operator, by turning the handle of the main cock 0, Fig. 1, onesixth of a revolution, (its further movement being arrested by suitable stops,) will admit a flow of air from the main G to the passage S, and thence through the open ports in cock D to the main pipe H, and out to the switchpiston cylinder, its passage into the opposite main pipe I through the cross-pipes X X being prevented by the closed valves 1) b. The admission of air to one end of the switch-cylinder will instantly operate to force its piston over, carrying with it the switch-rails V. So soon, however, as the rails have been forced over, the stem of the valve 1), which has prevented a flow of air through the cross-pipe X, will be struck thereby and the valve b be thrown open, allowing the air to pass from the pipe H directly to thepipe I. The air thus admitted to the second main pipe I will pass back through the open port in the cock D to the passage L, and thence through the pipe T, and, bearing against the indicating-piston, will force it over, changing thereby the position of the slide Q, so that the letter S will appear at the dial-opening 1", instead of the letter N, and, simultaneously turning the cock D one-sixth of a revolution, will not only close the communication between the supply-passage S and the main pipe H, and thus cut off a further supply of air from G, but will also open an outward ventfrom the pipe H, through passage L and port in cock 0, to the exhaustopening in passage F, and from pipe I, through passage S and port in cock 0, to passage L, pipe T, and exhaust-opening in cylinder B, the change in position of the cock D being indicated by the movement of the pointer W from letter N to letter S on the face of the board R.

By means of this apparatus an unerring and exact indication is given in the signal-station, from whence the movement of a switch is directed, of the change produced in the position of the switch, so soon as the change is fully and properly accomplished, but not otherwise; and a pressure of air directly from the airsupply pipe and compressing machinery is maintained upon the switch-piston until the switch has moved fully home, and is not cut ofi' until this fact has been indicated in the station.

'I claim as my invention 1. The cocks o and 1), combined with each other and with a pneumatic piston operating a railroad-switch, a second piston actuating said cock D, an air-supply main, exhaustvents, and suitable connecting-pipes, all substantially in the manner and for the purpose herein set forth.

2. In combination with the cock D and its actuating-piston M, and with the cock 0 and switch-piston K, a dial-board, R, and pointer W, arranged to indicate the position of said switch by the movement of the cock 1), substantially as herein set forth.

3. In combination with the movable rails of a railway-switch, and with cross-pipes X X, directly connecting the air-supply pipes H and I of a pneumatic piston operating said switch, valves b b, controlling said crosspipes, and arranged to determine the direction of the air-currents therein, and opened, respectively, by the movable switch-rails, when thrown to their normal position in the one direetion or the other, substantially as and for the purpose herein set forth.

DAVID A. BUBR. Witnesses:

J. M. BURR, A. T. SANGSTON. 

